2003 5.3 starts and dies after 5 seconds

[HemiSpeed]

I have a 5.3 swapped in an 87. I disabled VATS, wrote entire and now instead of running for 1 second and dying, now it runs for 5 seconds and dies.

I'm using a cheap aftermarket swap harness so I'm thinking that I may have a sensor that isnt reading and causing the engine to die. The engine doesn't seem to be going into closed loop.

What sensors not being connected would cause it to die after 5 seconds of running?


I've double and triple checked grounds. Added grounds from batt to body, frame, and engine.


Engine stock internals
SS2 cam
headers
cold air intake

[blindsquirrel]

MAP sensor is stuck at 14kPa. It should be equal to your location's pressure altitude (~100 at sea level, etc) at key-on, and then decrease as the engine fires.

[2xLS1]

And you are going have to get it running a lot longer than 5 seconds for it to go into closed loop.

[abc]

yep, start with diagnosing the MAPS circuit. Looks like you have the the linear and offset setup close enough for most 1 bar setups, so it's gonna be a wiring or sensor issue likely.

[HemiSpeed]

Alright, it was the MAP sensor. Robbed a MAP off of another and now it runs, not great, but it runs!

I need to wire in the IAT and MAF still to try to get it into closed loop.

It is backfiring out of one exhaust pipe and I can tell cylinder 5 isnt firing. Swapped coils and it doesnt follow the coil. I'm going to swap injectors now.

[abc]

yep, idle MAP is garbage right now. Your correct, find the problem/fix problem with the faulty cylinder, then log it again and report back.
For future reference, list cam specs. not just the fad name.

[HemiSpeed]

Alright, we went through the wiring for the coils and injectors and found that coil wires 5 and 8 were swapped in the China harness. Fixed that and checked the rest of the injector wires and everything else seems to match. The engine still runs rough and smells really rich. Does anything else stand out in the log?

[blindsquirrel]

Does this thing have full exhaust on it yet? The trims are adding a combined 75% and O2s are still reading lean, I suspect they aren't telling the truth.

[HemiSpeed]

I don't have full exhaust yet. Here is a log with the exhaust pipes slid on but not welded. I also raised idle rpm up to 950 rpm.

Cam is a 228/230 @ 50, 585/585 lift.

[HemiSpeed]

Also getting a P0174 system too lean bank 2 error. I have new o2 sensors that I'm going to swap in to see if that helps at all.

[blindsquirrel]

It won't ever be able to do closed loop without freaking the fk out until the O2s have 18-24" of pipe after them at an absolute minimum, so that they aren't constantly being diluted with big gulps of outside air on every exhaust pulse.

[HemiSpeed]

Okay, we have the exhaust welded up and we swapped out the bad o2 sensor and the LT and ST trims look better now. It still seems to run a little rough. Does anything here look weird?run4.hpl

[blindsquirrel]

Fuel System #1 Status (SAE) CL - Fault

[HemiSpeed]

What causes that error?

[blindsquirrel]

You did a swap and kept the donor's catalytic converters, and downstream O2s, and the BCM, and DIC, and ABS, and all of the other crap that's not been turned off in the tune file? Of course, I'm going by the file you posted a week ago, if you've made any changes since then the file that produced the log needs to be posted too. If you post a log and nothing in the tune has been changed, you need to state that clearly.

What O2 sensors did you put in it (brand, part number, source)? Is the harness isolated ground or case ground and do you have sensors that match whichever one the harness is?

[TheMechanic]

I'm thinking you may want to change out the spark plugs at this point also. Bet they are fouled like crazy.

[blindsquirrel]

(rage-induced aside: When I track down the asshole responsible for converting the whole interwebs into this daycare-style relative date/relative time thing instead of an actual date and actual timestamp, I'm going to [REDACTED] and not lose the first second's sleep over it.)